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http://elar.urfu.ru/handle/10995/111506
Title: | Gas Phase Elemental Abundances in Molecular CloudS (GEMS) V. Methanol in Taurus |
Authors: | Spezzano, S. Fuente, A. Caselli, P. Vasyunin, A. Navarro-Almaida, D. Rodríguez-Baras, M. Punanova, A. Vastel, C. Wakelam, V. |
Issue Date: | 2022 |
Publisher: | EDP Sciences EDP Sciences |
Citation: | Gas Phase Elemental Abundances in Molecular CloudS (GEMS) V. Methanol in Taurus / S. Spezzano, A. Fuente, P. Caselli et al. — DOI 10.3390/polym13152520 // Astronomy and Astrophysics. — 2022. — Vol. 657. — A10. |
Abstract: | Context. Methanol, one of the simplest complex organic molecules in the interstellar medium, has been shown to be present and extended in cold environments such as starless cores. Studying the physical conditions at which CH3OH starts its efficient formation is important to understand the development of molecular complexity in star-forming regions. Aims. We aim to study methanol emission across several starless cores and investigate the physical conditions at which methanol starts to be efficiently formed, as well as how the physical structure of the cores and their surrounding environment affect its distribution. Methods. Methanol and C18O emission lines at 3 mm have been observed with the IRAM 30 m telescope within the large programme Gas phase Elemental abundances in Molecular CloudS towards 66 positions across 12 starless cores in the Taurus Molecular Cloud. A non-LTE (local thermodynamic equilibrium) radiative transfer code was used to compute the column densities in all positions. We then used state-of-the-art chemical models to reproduce our observations. Results. We have computed N(CH3OH)/N(C18O) column density ratios for all the observed offsets, and the following two different behaviours can be recognised: the cores where the ratio peaks at the dust peak and the cores where the ratio peaks with a slight offset with respect to the dust peak (∼10 000 AU). We suggest that the cause of this behaviour is the irradiation on the cores due to protostars nearby which accelerate energetic particles along their outflows. The chemical models, which do not take irradiation variations into account, can reproduce the overall observed column density of methanol fairly well, but they cannot reproduce the two different radial profiles observed. Conclusions. We confirm the substantial effect of the environment on the distribution of methanol in starless cores. We suggest that the clumpy medium generated by protostellar outflows might cause a more efficient penetration of the interstellar radiation field in the molecular cloud and have an impact on the distribution of methanol in starless cores. Additional experimental and theoretical work is needed to reproduce the distribution of methanol across starless cores. © S. Spezzano et al. 2021. |
Keywords: | ISM: CLOUDS ISM: MOLECULES RADIO LINES: ISM CLOUDS DUST GASES IRRADIATION MOLECULES RADIATIVE TRANSFER CHEMICAL MODEL COLUMN DENSITY ELEMENTAL ABUNDANCE GAS-PHASES ISM : CLOUDS ISM:MOLECULES MOLECULAR CLOUDS PHYSICAL CONDITIONS RADIO LINES: ISM SIMPLE++ METHANOL |
URI: | http://elar.urfu.ru/handle/10995/111506 |
Access: | info:eu-repo/semantics/openAccess |
RSCI ID: | 47552073 |
SCOPUS ID: | 85122251526 |
WOS ID: | 000733019300002 |
PURE ID: | 29226409 |
ISSN: | 0004-6361 |
DOI: | 10.1051/0004-6361/202141971 |
metadata.dc.description.sponsorship: | Acknowledgements. The authors are grateful to the anonymous referee for insightful comments. A large part of the data analysis described in this paper was performed during the spring of 2020, in the beginning of the COVID pandemic and during a hard lockdown. S.S. wishes to thank the Max Planck Society for the flexibility that was allowed during the pandemic, because it contributed to maintaining a clear and focus mind during the hours that she could dedicate to her work, and overall to keep calm, while waiting for the ‘storm’ to pass. Based on analysis carried out with the CASSIS software (http://cassis.irap. omp.eu) and CDMS and JPL spectroscopic databases and LAMDA molecular databases. CASSIS has been developed by IRAP-UPS/CNRS. S.S. wishes to thank the Max Planck Society for the Independent Max Planck Research Group funding. A.F., D.N.A. and M.R.B. are funded by Spanish MICINN through PID2010-106235GB-I00 national research project. V.W. acknowledges the CNRS program Physique et Chimie du Milieu Interstellaire (PCMI) co-funded by the Centre National d’Etudes Spatiales (CNES). A.V. and A.P. are the members of the Max Planck Partner Group at the Ural Federal University. A.V. and A.P. acknowledge the support of the Russian Ministry of Science and Education via the State Assignment Contract no. FEUZ-2020-0038. |
Appears in Collections: | Научные публикации ученых УрФУ, проиндексированные в SCOPUS и WoS CC |
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